Add support to handle multiple writeback contexts and check for
dirty_exceeded across all the writeback contexts.

Made a new helper for same.

Signed-off-by: Kundan Kumar <kundan.kumar@samsung.com>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
---
 fs/f2fs/node.c              |  4 ++--
 fs/f2fs/segment.h           |  2 +-
 include/linux/backing-dev.h | 18 +++++++++++++++---
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 1693da9417f9..cd75aa98a1ca 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -73,7 +73,7 @@ bool f2fs_available_free_memory(struct f2fs_sb_info *sbi, int type)
 		if (excess_cached_nats(sbi))
 			res = false;
 	} else if (type == DIRTY_DENTS) {
-		if (sbi->sb->s_bdi->wb_ctx[0]->wb.dirty_exceeded)
+		if (bdi_wb_dirty_limit_exceeded(sbi->sb->s_bdi))
 			return false;
 		mem_size = get_pages(sbi, F2FS_DIRTY_DENTS);
 		res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 1);
@@ -114,7 +114,7 @@ bool f2fs_available_free_memory(struct f2fs_sb_info *sbi, int type)
 		res = false;
 #endif
 	} else {
-		if (!sbi->sb->s_bdi->wb_ctx[0]->wb.dirty_exceeded)
+		if (!bdi_wb_dirty_limit_exceeded(sbi->sb->s_bdi))
 			return true;
 	}
 	return res;
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 7e5b7b1a5d2b..8487bd5d4394 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -993,7 +993,7 @@ static inline bool sec_usage_check(struct f2fs_sb_info *sbi, unsigned int secno)
  */
 static inline int nr_pages_to_skip(struct f2fs_sb_info *sbi, int type)
 {
-	if (sbi->sb->s_bdi->wb_ctx[0]->wb.dirty_exceeded)
+	if (bdi_wb_dirty_limit_exceeded(sbi->sb->s_bdi))
 		return 0;
 
 	if (type == DATA)
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 59bbb69d300c..bb35f8fa4973 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -51,6 +51,21 @@ static inline bool wb_has_dirty_io(struct bdi_writeback *wb)
 	return test_bit(WB_has_dirty_io, &wb->state);
 }
 
+#define for_each_bdi_wb_ctx(bdi, wbctx) \
+	for (int __i = 0; __i < (bdi)->nr_wb_ctx \
+		&& ((wbctx) = (bdi)->wb_ctx[__i]) != NULL; __i++)
+
+static inline bool bdi_wb_dirty_limit_exceeded(struct backing_dev_info *bdi)
+{
+	struct bdi_writeback_ctx *bdi_wb_ctx;
+
+	for_each_bdi_wb_ctx(bdi, bdi_wb_ctx) {
+		if (bdi_wb_ctx->wb.dirty_exceeded)
+			return true;
+	}
+	return false;
+}
+
 static inline bool bdi_has_dirty_io(struct backing_dev_info *bdi)
 {
 	/*
@@ -149,9 +164,6 @@ static inline bool mapping_can_writeback(struct address_space *mapping)
 }
 
 #define DEFAULT_WB_CTX 0
-#define for_each_bdi_wb_ctx(bdi, wbctx) \
-	for (int __i = 0; __i < (bdi)->nr_wb_ctx \
-		&& ((wbctx) = (bdi)->wb_ctx[__i]) != NULL; __i++)
 
 static inline struct bdi_writeback_ctx *
 fetch_bdi_writeback_ctx(struct inode *inode)
-- 
2.25.1